I have lowered many r6 models just altering the lentgh of the dogbones would do it but the bike will not sit level and the rake and trail will alter you should lower the bike evenly ie dogbones and drop forks through to match this will reduce ground clearance though.
Longer doglegs bones also make the bike sit upright more on the sidestand making it more prone to falling over.
every 6000 thousand miles or one year
6k minor service
12k major service
18k minor service
24k major plus valve clearance checks
each service adds different levels of checks as the mileage increases ie fork oil change , brake fluid change, etc.
and perishables such as pads/tyres as you wear them out.